Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Active dropout optimization for current mode LDOs

a current mode and dropout optimization technology, applied in the direction of power conversion systems, instruments, process and machine control, etc., can solve the problems of considerable ripple in the output voltage of a conventional dc/dc converter operating in a switched mode, and considerable efficiency loss, so as to avoid efficiency loss

Active Publication Date: 2006-02-16
TEXAS INSTR INC
View PDF18 Cites 24 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present invention provides a DC / DC converter with a linear regulator that reduces or eliminates output ripple with minimal loss of efficiency. The converter includes a converter stage, a regulator stage, and a tracking circuit. The tracking circuit controls the converter stage to increase the converted voltage with an increasing load sense current and vice versa, so that the output voltage of the converter is always just sufficient to eliminate the ripple without having to operate the regulator's pass transistor in its linear range. The linear regulator includes a load current pass transistor in MOS technology, and the tracking circuit ensures that the voltage at the converted voltage output of the converter stage is just sufficient to avoid operation of the load current pass transistor in an unsaturated state, resulting in a loss of efficiency.

Problems solved by technology

The output voltage of a conventional DC / DC converter operating in a switched mode usually has a considerable ripple.
As a consequence, the load current pass transistor in the voltage regulator usually operates in an unsaturated condition, resulting in a considerable loss of efficiency.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Active dropout optimization for current mode LDOs
  • Active dropout optimization for current mode LDOs
  • Active dropout optimization for current mode LDOs

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0009] The DC / DC converter in FIG. 1 comprises a converter stage 10, a current mode LDO (Low Dropout regulator or Linear Dropout regulator) 12 and a Dropout Tracking Circuit 14. An input voltage VIN of a system is converted (by means of a Buck-, Boost-Converter, Charge Pump, or other suitable means) to a certain output converter voltage at VBOOT (see FIG. 1). A current mode LDO converts the relative high ripple voltage at VBOOT to a low ripple voltage at VMAIN. The dropout tracking circuit compares the voltages VBOOT with VMAIN and sends a Control Signal which is dependent on the load current ILOAD to the voltage converter (e.g., to change Duty Cycle of the Voltage Converter). The goal of this configuration is a low ripple output voltage VMAIN without high efficiency losses. To minimize the efficiency losses the dropout of the Linear Dropout Regulator is regulated via the dropout tracking circuit.

[0010]FIG. 2 shows further details of a particular implementation. In the Current Mode...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

A DC / DC converter has a linear voltage regulator for reducing or eliminating the output ripple of the converter with a minimum loss of efficiency. The converter comprises a converter stage with a supply voltage input, a converted voltage output and a control input, a regulator stage having an input connected to the converted voltage output of the converter stage and an output connected to a load, and a tracking circuit with inputs for a voltage at the converted voltage output of the converter stage, a voltage at the output of the regulator stage and a load sense current, and an output connected to the control input of the converter stage. The tracking circuit controls the converter stage so as to increase the converted voltage with an increasing load sense current and vice versa. The output voltage of the converter is always just sufficient to eliminate the ripple without having to operate the regulator's pass transistor in its linear range.

Description

[0001] The present invention relates to a DC / DC converter with a linear regulator for reducing the output ripple of the converter. BACKGROUND OF THE INVENTION [0002] The output voltage of a conventional DC / DC converter operating in a switched mode usually has a considerable ripple. This is especially the case for converters with hysteretic control. When such ripple cannot be tolerated for a particular application, a linear regulator is inserted between the output of the converter stage and the load to eliminate the ripple. Since the voltage regulator is not aware of the load requirements, the output voltage of the converter is adjusted to a level sufficient for the regulator to eliminate the ripple under all load conditions. As a consequence, the load current pass transistor in the voltage regulator usually operates in an unsaturated condition, resulting in a considerable loss of efficiency. BRIEF SUMMARY OF THE INVENTION [0003] The present invention provides a DC / DC converter with ...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(United States)
IPC IPC(8): G05F1/56
CPCH02M2001/0045G05F3/262H02M1/0045
Inventor THIELE, GERHARDBAYER, ERICH
Owner TEXAS INSTR INC
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com